Evaluation of a modified QuEChERS extraction of multiple classes of pesticides from a rice paddy soil by LC-APCI-MS/MS

Soil dissipation and efficacy on itchgrass of soil-applied residual herbicides pendimethalin and clomazone in Louisiana sugarcane

BACKGROUND

Sugarcane (Saccharum sp.) growers in Louisiana report that the widely used soil residual herbicide, pendimethalin, is less effective at controlling itchgrass (Rottboellia chochinchinensis), possibly through accelerated dissipation from repeated applications. Some growers have started to use another herbicide, clomazone, in place of pendimethalin for itchgrass control when pendimethalin does not provide the necessary control. Little is known about the dissipation of these two herbicides, especially when applied together, in diverse sugarcane soils in Louisiana. Thus, the objective of the research was to measure the dissipation of pendimethalin and clomazone in soils having high itchgrass pressure. Soil samples from five fields were fortified (4 μg g-1) with clomazone and pendimethalin and monitored over the course of 163 days under laboratory conditions. Herbicide levels were determined by extracting the herbicides from soil with acetonitrile and analyzing the extracts with high performance liquid chromatography (HPLC).

RESULTS

The results indicate that clomazone is persistent in the soils studied, with a degradation half-life (DT50) of ≥79 days. Pendimethalin dissipates more rapidly in soil with a DT50 ranging from 7 to 59 days. All itchgrass plants showed injury to herbicide but many grew out of symptoms, and responses were not consistent between soil types.

CONCLUSION

Pendimethalin dissipation varied greatly between soil types, yet clomazone was generally persistent in each soil tested. However, when these soils were seeded with itchgrass, pendimethalin was more effective at controlling itchgrass than clomazone. Although persistent in the soils tested, the leaching potential of clomazone may limit its long-term effectiveness. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Optimizing the QuEChERS method for efficient monitoring of fipronil, thiobencarb, and cartap residues in paddy soils with varying properties

This study aims to optimize the QuEChERS methodology for extracting three pesticides (fipronil, thiobencarb, and cartap) from two paddy soils with distinct characteristics. Various modifications were explored to enhance extraction efficiency, employing acetonitrile (MeCN) or ethyl acetate (EtOAc) for extraction and primary-secondary amine (PSA) and graphitized carbon black (GCB) for the clean-up. Assessment criteria included accuracy, precision, linearity, detection limits, uncertainty, and matrix effects. Results revealed that the clayey soil with lower organic carbon (OC) content (1.26%) and 100% moisture yielded the highest pesticide recoveries (113.72%, 115.73%, and 116.41% for FIP, THIO, and CART, respectively). In contrast, the silty clayey soil with higher OC content (2.91%) and 20% water content exhibited poor recoveries (< 60%). FIP and CART demonstrated better recoveries with MeCN, while THIO performed better with EtOAc under specific moisture conditions. Clean-up sorbents significantly reduced FIP and CART recoveries, with THIO recoveries less affected. Acidifying with HCl substantially improved CART recovery. EtOAc introduced a moderate to strong matrix effect for FIP and THIO, while MeCN in soils with 100% moisture resulted in a strong matrix effect for CART. The study highlighted the substantial impact of extraction conditions, pesticide properties, and soil conditions on the outcomes of the QuEChERS method. A comprehensive understanding of these interplays was deemed crucial for accurately quantifying pesticide residues in agricultural soils.

Optimization and validation of an extraction method for the analysis of multi-class emerging contaminants in soil and sediment

Analytical methods for the determination of multi-class emerging contaminants are limited for soil and sediment while they are essential to provide a more complete picture of their distribution in the environment and to understand their fate in different environmental compartments. In this paper, we present the development and optimization of an analytical strategy that combines reliable extraction, purification and the analysis using ultra-pressure liquid chromatography triple quadrupole mass spectrometry (UPLC-MS/MS) of 90 emerging organic contaminants including pesticides, pharmaceuticals and personal care products, flame retardants, per- and polyfluoroalkyl substances (PFASs) and plasticizers in soil and sediment. To extract a wide range of chemicals, the extraction strategy is based on the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach. A number of different options were investigated (buffer, acidification, addition of EDTA, different types and combinations of dispersive SPE etc.) and the effectiveness of the chemical extraction procedure and the clean-up was assessed for two matrices: soil (organic matter content of 9%) and sediment (organic matter content of 1.9%). The method was fully validated for both matrices, in terms of accuracy, linearity, repeatability (intra-day), reproducibility (inter-day), method limits of detection and quantification (LODs and MLOQs, respectively). The final performance showed good accuracy and precision (mean recoveries were between 70 and 120% with relative standard deviations (RSD) less than 20% in most cases), low matrix effects, good linearity for the matrix-matched calibration curve (R2≥0.991) and MLOQs ranged from 0.25 and 10 µg/kg. To demonstrate the applicability and suitability of the validated method, soil and sediment samples from Vietnam, France, Sweden and Mexico were analyzed. The results showed that of the 90 target compounds, a total of 33 were quantified in the sediment and soil samples analyzed. In addition to multi-target analysis, this strategy could be suitable for non-target screening, to provide a more comprehensive view of the contaminants present in the samples.

Determination of 73 multi-class pesticides in okra (Abelmoschus esculentus L.) fruits using LC-MS/MS and GC-MS/MS and estimation of analytical uncertainty of measurement

This study developed a method to simultaneously determine 73 multi-class pesticides in okra fruit using LC-MS/MS and GC-MS/MS. The sample was extracted with acetonitrile and subsequent clean-up through dispersive-SPE method. The quantification level of the technique was 0.01 µg g-1 and compliance to the MRLs fixed by the regulatory bodies like EU and FSSAI. The recovery at 10, 50, and 100 µg kg-1 spiked levels; intra and inter-day precision at 50 µg kg-1 were found within 70-120% with RSD less than 15% with LC-MS/MS and GC-MS/MS. Measurement uncertainty was in the range of 1.81 to 12.91 µg kg-1 estimated at 50 µg kg-1. The matrix effects were slightly higher for LC than GC-compatible pesticides. Risk assessment for pesticides detected in the field and market samples found no hazardous to the consumers except profenofos. The proposed method is highly sensitive, reproducible for the complex matrix like okra, and meets the regulatory standards.

A multi-residue method for trace analysis of pesticides in soils with special emphasis on rigorous quality control

A multi-residue trace analytical method is presented to accurately quantify 146 currently used pesticides in (agricultural) soils with varying soil properties. Pesticides were extracted using an optimized quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach and chemical analysis was carried out by liquid chromatography coupled to tandem mass spectrometry (triple quadrupole). Quantification was based on matrix-matched internal standards calibration, using 95 isotopically labeled analyte analogues. In contrast to the common approach of method validation using soils freshly spiked with analytes shortly before the extraction, our method is additionally validated via an in-house prepared partly aged soil, which contains all target pesticides and via agricultural field soils with native pesticide residues. The developed method is highly sensitive (median method limit of quantification: 0.2 ng/g), precise (e.g., median intra-day and inter-day method precision both ~ 4% based on field soils), and true ((i) quantified pesticide concentrations of the partly aged soil remained stable during 6 months, were close to the initially spiked nominal concentration of 10 ng/g, and thus can be used to review trueness in the future; (ii) median freshly spiked relative recovery: 103%; and (iii) participation in a ring trial: median z-scores close to one (good to satisfactory result)). Its application to selected Swiss (agricultural) soils revealed the presence of in total 77 different pesticides with sum concentrations up to 500 ng/g. The method is now in use for routine soil monitoring as part of the Swiss Action Plan for Risk Reduction and Sustainable Use of Plant Protection Products.

Study and voltammetric determination of fipronil in bovine lactose-free milk by differential pulse voltammetry using a carbon paste electrode

A novel voltammetric screening method has been developed for the rapid determination of fipronil (FPN) residues in lactose-free milk samples with the use of a carbon-paste electrode (CPE) by differential-pulse voltammetry (DPV). Cyclic voltammetry indicated the occurrence of an irreversible anodic process at approximately +0.700 V (vs. Ag|AgCl, 3.0 mol L^-1 KCl) in a 0.100 mol L^-1 NaOH supporting electrolyte prepared as a 30% (v/v) ethanol-water solution. Quantification of FPN was carried out by DPV and analytical curves were constructed. In the absence of a matrix, the limits of detection (LOD) and quantification (LOQ) were 0.568 mg L^-1 and 1.89 mg L^-1, respectively. In the presence of a lactose-free skim milk matrix, the values of LOD and LOQ were 0.331 mg L^-1 and 1.10 mg L^-1. The recovery percentages for three different concentrations of FPN in lactose-free skim milk samples ranged between 95.3% and 109%. All assays could be conducted with milk samples without any prior extraction steps or pre-concentration of FPN, making this novel method rapid, simple, and relatively cheap.

Multiresidue analysis of pesticides in three Indian soils: method development and validation using gas chromatography tandem mass spectrometry

The paper reports a multiresidue method that was validated on 220 multi-class pesticides in three major Indian soils, namely, (i) new alluvial soil (NAS); (ii) red lateritic soil (RS) and (iii) black soil (BS) from three different regions. An ethyl acetate-based extraction method with a freezing-out cleanup step was employed for sample preparation, followed by gas chromatography-tandem mass spectrometric analysis. The method that was initially optimized on BS worked satisfactorily for the other two soil matrices. At the spiking level of 10 µg/kg (LOQ), the recoveries were satisfactory (within 70-120%) with precision-RSDs, ≤20% (n = 6) for 85, 88.6, and 89% of compounds in BS, RS, and NAS respectively. At 20 µg/kg, the method performance was satisfactory in each soil for all pesticides. When this validated method was applied to analyse 25 field samples, 6 pesticides were detected in them. In each case, precision (RSD) was <20%. The method sensitivity, accuracy and precision complied with the SANTE/2020/12830 guidelines. The method can be applied for environmental monitoring and risk assessment purposes, thus aiding in regulating pesticide usage in agricultural fields. The limitations and future scope of the study are also discussed.HighlightsA multiresidue method is reported for simultaneous analysis of multi-class pesticides in diverse soilsThe method was validated on 220 pesticides in new alluvial, red lateritic and black soilsSample preparation involved extraction with ethyl acetate and cleanup by a freezing stepThe residues were estimated by gas chromatography tandem mass spectrometry (GC-MS/MS)The method accuracy and precision complied with the EU's SANTE guidelines.

Novel fast pesticides extraction (FaPEx) strategy coupled with UHPLC-MS/MS for rapid monitoring of emerging pollutant fipronil and its metabolite in food and environmental samples

In this work, we demonstrated a new, environmental-friendly and effective sample preparation strategy named 'in-syringe-assisted fast pesticides extraction (FaPEx)' technique coupled with LC-MS/MS for the rapid identification and monitoring of emerging pollutant fipronil and its metabolite fipronil sulfone in chicken egg and environmental soil samples. FaPEx strategy comprising of two simple steps. Firstly, the sample was placed in the syringe and extracted using low-volume acetonitrile with NaCl and anhydrous MgSO₄ salts. Secondly, the extractant was passed through in-syringe-based solid-phase extraction (SPE) kit containing cleanup sorbents and salt combinations (C18, primary secondary amine, and anhydrous MgSO₄) for the cleanup process. Then, the obtained clean extractant was injected into LC-MS/MS for the quantification of target analytes. Various important parameters influencing the FaPEx performances, such as solvent type, salt type, salt amount, sorbent type, and amount, were examined and optimized. The method validation results showed excellent linearity with high correlation coefficients were ≥ 0.99. The estimated LODs were between 0.05-0.07 μg/kg, and LOQs ranged between 0.1-0.25 μg/kg for target analytes in both egg and soil sample matrices, and precision values were ≤7.90%. The developed method was applied to commercial chicken egg samples and environmental soil samples analysis. Spiked recoveries ranged between 88.75-110.91% for egg samples with RSDs ≤7.42% and 82.47-107.46% for soil samples with RSDs <7.37%. These results proved that the developed sample preparation method is a simple, fast, green, low-cost, and efficient method for the analysis of fipronil and its metabolites in food and environmental samples. Thus, this method can be applied as an alternative analytical methodology in routine and standard food and environmental testing laboratories.

Spatial-temporal occurrence of contaminants of emerging concern in urban rivers in southern Brazil

The widespread use and misuse of antibiotics and pesticides has been linked with several risks to the environment and human health. In the present report, the results of the monitoring of 64 pharmaceuticals and 134 pesticides occurrence in an urban river in Southern Brazil are presented and discussed. Sampling campaigns have covered the period 2016-2018. The identification and determination of the analytes were achieved by high-resolution mass spectrometry. The data were analyzed using chemometric tools to obtain spatial-temporal models. Toxicological evaluation was achieved using acute toxicity (zebrafish standardized protocol), and determination of risk quotient. Within the 198 analytes included in the targeted analysis method for surface water, 33 were identified in an urban river during 2 years of monitoring, being 20 pharmaceuticals and 13 pesticides. Using high-resolution mass spectrometry, a suspect screening approach was established in an un-target analysis. The evaluation was carried out using a data bank built from consumption data of drugs and pesticides, in the metropolitan region of Porto Alegre - RS and their respective metabolites. The suspect screening analysis done with a data bank with more than 1450 compounds results in 27 suspect findings. The target analysis results showed a continuous prevalence of non-steroidal anti-inflammatories, analgesics, antipyretics, beta-blockers, corticoids, and antibiotics. Regarding the pesticides, the main classes were fungicides, especially those from triazol and strobilurin classes.

Pesticide-Residue Analysis in Soils by the QuEChERS Method: A Review

Pesticides are among the most important contaminants worldwide due to their wide use, persistence, and toxicity. Their presence in soils is not only important from an environmental point of view, but also for food safety issues, since such residues can migrate from soils to food. However, soils are extremely complex matrices, which present a challenge to any analytical chemist, since the extraction of a wide range of compounds with diverse physicochemical properties, such as pesticides, at trace levels is not an easy task. In this context, the QuEChERS method (standing for quick, easy, cheap, effective, rugged, and safe) has become one of the most green and sustainable alternatives in this field due to its inherent advantages, such as fast sample preparation, the minimal use of hazardous reagents and solvents, simplicity, and low cost. This review is aimed at providing a critical revision of the most relevant modifications of the QuEChERS method (including the extraction and clean-up steps of the method) for pesticide-residue analysis in soils.

Simultaneous multi-residue pesticide analysis in southern Brazilian soil based on chemometric tools and QuEChERS-LC-DAD/FLD method

A simple and straightforward QuEChERS extraction method was proposed for the simultaneous determination of atrazine (ATZ), desethylatrazine (DEA), desisopropylatrazine (DIA), carbaryl (CBL), carbendazim (CBD), and diuron (DIU) in soil with high agricultural activity from southeastern Brazil, using high-performance liquid chromatography-diode-array detection/fluorescence detection. Screening studies carried out by 2⁴ factorial design indicate better recoveries when less sample (1.0 g) and the volume of solvent (2.0 mL of ACN) were applied, compared to the original QuEChERS method. Furthermore, interactions between factors were not negligible in the experimental set, except for ATZ and DIU, in which only water volume influenced their recovery. The influence of the type (primary secondary amine (PSA), C18, and Florisil) and the sorbent amount ratio to the compounds' concentration were also considered. PSA (25 mg) was selected as the best sorbent without losing analytical response. The limits of quantification (LOQ) were estimated to be 5.0 to 15 µg kg^-1 in the soil matrix. Analytical performances were consistent with linearity (R² ≥ 0.998), recovery from 74.7 to 108%, and relative standard deviations (RSD) between 2.6 and 20.2%. Robustness was assessed by fractional factorial Plackett-Burman design. The method is recommended for chemicals that are soluble in water, and it was successfully applied in the analysis of real soil samples containing the analytes in the range of μg kg^-1, proving to be suitable for the study of soils strongly impacted by agricultural activity.

Targeted Multiresidue Method for the Analysis of Different Classes of Pesticides in Agro-Food Industrial Sludge by Liquid Chromatography Tandem Mass Spectrometry

Sludge generated after washing of fruits and vegetables during agro-food processes is a complex matrix and selective methods for the identification and quantification of pesticides’ residues are necessary in order to achieve a sustainable and effective management of the total sewage. The present work describes the development and validation of a reliable, simple and fast analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of 47 pesticides of different chemical classes, including organosphosphates, pyrethroids, neonicotinoids, triazoles and others, in sludge samples after QuEChERS sample preparation. The necessity of the individual steps of QuEChERS was investigated and the LC-ESI-MS/MS conditions were optimized to achieve maximum sensitivity of the target analytes. The method limits of detection (LODs) ranged between 0.0005 mg/kg (imidacloprid) and 0.05 mg/kg (beta cyfluthrin). The recoveries ranged between 71–120% and the repeatability of the method was ≤25% expressed as relative standard deviation. The method was applied to sludge samples generated after washing of fruits in an agro-fruit-packaging unit in Greece. The results showed the presence of 37 pesticides’ active substances with concentrations ranging from low ppbs, such as fludioxinil (5 μg/kg) up to low ppms such as beta cyfluthrin (3.5 mg/kg) and with their sum concentration reaching up to 19 mg/kg.

Residues and dietary intake risk assessments of clomazone, fomesafen, haloxyfop-methyl and its metabolite haloxyfop in spring soybean field ecosystem

Soybean is an important oilseed crop, but weed can have a significant effect on soybean yield. Clomazone, fomesafen, and haloxyfop-methyl are high-efficacy herbicides, and the combination of these herbicides shows an ideal effect on weed control. However, the residues of these herbicides and their impacts on human health are still largely unknown. In the current study, a rapid, sensitive, and selective method using modified QuECHERS procedure combined with HPLC-MS/MS was established to detect these herbicides in soybean matrices. The limits of quantification were 0.01, 0.01 and 0.025 mg/kg for haloxyfop-methyl, haloxyfop and fomesafen, and 0.005, 0.005 and 0.0125 mg/kg for clomazone in green soybean, soybean grain, and straw, with the average recoveries ranging from 80% to 107%. The terminal residues of the target compounds were all below the corresponding limits of quantification. The dietary risk assessment showed that the risk quotient values were far below the acceptable human consumption levels.

Simultaneous determination of pharmaceuticals and metabolites in fish tissue by QuEChERS extraction and UHPLC Q/Orbitrap MS analysis

In recent years, the occurrence, fate, and adverse effects of pharmaceutically active compounds (PhACs) in aquatic organisms have become a noteworthy issue. In the present study, a rapid and sensitive multiresidue analytical method was developed for the determination of 18 parent PhACs and 5 metabolites in sea bream (Sparus aurata), by combining a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) procedure with ultra-high performance liquid chromatography-Orbitrap-mass spectrometry (UHPLC-Orbitrap-MS). The method development involved optimization of extraction solvent, extraction salts, clean-up sorbents, and amount of sample evaluation, while identification on Orbitrap MS was based on accurate mass and further confirmation with MS/MS fragmentation. The developed method was validated, and linearity was higher than 0.99. Recoveries in all cases ranged between 62 and 107% (at 10, 50, and 100 ng g^-1), while intra-day and inter-day precision, expressed as relative standard deviation, RSD, was lower than 4% and 7%, respectively. In addition, limits of quantification (LOQs) ranged between 0.5 and 19 ng g^-1. The compounds presented a low matrix effect, between - 13 and 4%, while the expanded uncertainty U% estimated at the three spiking levels 10, 50, and 100 ng g^-1 was found below 49% in all cases. Finally, the validated method was applied to sea bream samples from an aquaculture farm located in the Mediterranean Sea, with one positive finding for the antibiotic trimethoprim at a concentration of 26 ng g^-1, presenting negligible human health risk.

Determination study of contaminants of emerging concern at trace levels in agricultural soil. A pilot study

In this study, we aimed to develop and validate a quick, easy, and robust extraction method for the simultaneous determination of 30 organic contaminants of emerging concern (CECs) including some transformation products in soil samples. Three different extraction methods based on an ultrasonic cylindrical probe (UAE), a pressurized liquid extraction (PLE), and a QuEChERS method were compared. Ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS) was used for identification and quantification of the target analytes. A modified QuEChERS method showed the best results in terms of extractability and accuracy. The extraction procedure developed provided adequate extraction performances (70% of the target analytes were recovered within a 70-99% range), with good repeatability and reproducibility (variations below 20%) and great sensitivity (LOQ < 0.1 ng/g in most cases). No matrix effects were observed for 70% of the compounds. Finally, the analytical methodology was applied in a pilot study where agricultural soil was irrigated with reclaimed water spiked with the contaminants under study. Of the 25 CECs added in irrigation water, a total of 13 pesticides and 5 pharmaceutical products were detected at concentration ranges from 0.1 to 1.2 ng/g (d.w) and from 0.1 to 2.0 ng/g (d.w), respectively.

Determination of 77 Multiclass Pesticides and Their Metabolitesin Capsicum and Tomato Using GC-MS/MS and LC-MS/MS

A quick, sensitive, and reproducible analytical method for the determination of 77 multiclass pesticides and their metabolites in Capsicum and tomato by gas and liquid chromatography tandem mass spectrometry was standardized and validated. The limit of detection of 0.19 to 10.91 and limit of quantification of 0.63 to 36.34 µg·kg⁻¹ for Capsicum and 0.10 to 9.55 µg·kg⁻¹ (LOD) and 0.35 to 33.43 µg·kg⁻¹ (LOQ) for tomato. The method involves extraction of sample with acetonitrile, purification by dispersive solid phase extraction using primary secondary amine and graphitized carbon black. The recoveries of all pesticides were in the range of 75 to 110% with a relative standard deviation of less than 20%. Similarly, the method precision was evaluated interms of repeatability (RSDr) and reproducibility (RSD_wR) by spiking of mixed pesticides standards at 100 µg·kg⁻¹ recorded anRSD of less than 20%. The matrix effect was acceptable and no significant variation was observed in both the matrices except for few pesticides. The estimated measurement uncertainty found acceptable for all the pesticides. This method found suitable for analysis of vegetable samples drawn from market and farm gates.

Validation of an Analytical Workflow for the Analysis of Pesticide and Emerging Organic Contaminant Residues in Paddy Soil and Rice

Contamination of agricultural soil with organic contaminants is a global problem due to the risks associated with food security and ecological sustainability. Besides the use of agrochemicals, hundreds of emerging contaminants enter arable lands through polluted irrigation water. In this study, an analytical workflow based on QuEChERS extraction coupled with LC-MS/MS quantification was applied to measure 65 emerging contaminants (42 pesticides and 23 multiclass industrial chemicals) in soil and rice for the first time. The method was validated on paddy and yard soil and rice plants. A recovery efficiency ranging between 70 and 120% (RSD <20%) was achieved for more than 70% of the analytes. Then, the validated method was used to quantify target contaminants in 22 soil and 9 rice samples collected mainly from paddy fields close to the Ergene River (Turkey), which is a highly polluted river used for irrigation in the region. Pesticide residues were present in all soil samples up to 2.4 mg/kg. However, their concentrations were below their maximum residual limits in rice. Azoxystrobin, prochloraz, propiconazole, imidacloprid, and epoxiconazole were the most frequently detected pesticides. In addition, industrial pollutants such as benzyldimethyldodecylammonium and tris(2-butoxyethyl) phosphate were detected in paddy soil samples at concentrations between 0.1 and 691 μg/kg. Benzyldimethyldodecylammonium and 5-methyl-1H benzotriazole were also measured in rice at concentrations up to 0.26 and 2.13 μg/kg, respectively.

Optimization and validation of a QuEChERS-based method for the simultaneous environmental monitoring of 218 pesticide residues in clay loam soil

A modified QuEChERS method was optimized, validated and verified for the extraction of 218 pesticide residues in agricultural soil samples. The 218 analytes are extracted using a single step, without clean-up, with matrix-matched calibration, and two complementary techniques: liquid and gas chromatography tandem triple quad mass spectrometry (LC-MS/MS and GC-MS/MS). Some of the parameters such as salts, acidity of the extraction solvent, sample moisture and some mechanical changes in the procedure were optimized to improve the overall performance for the target compounds and the soil matrix. The method was fully validated on a representative agricultural soil sample of the Canary Islands (clay loam soil) in terms of linearity, accuracy and precision. To avoid matrix effects, matrix-matched calibration curves (R² ≥ 0.99) were used for all target analytes. 100% of the compounds can be quantified with limits of quantification (LOQ) lower than the limit typically used in soils (50 ng g^-1), with 92% of compounds presenting a LOQ that is at least 10 times lower than that normally required. The limits of detection (LOD) ranged between 0.024 and 6.25 ng g^-1. The validated method was applied to a series of actual samples of agricultural soil (n = 18). In addition, as a further verification of its potential, the results of the application of the method in the investigation of clay loam soil samples that were obtained from underneath wildlife carcasses in the context of an environmental forensic investigation are also presented.

Comparison of high resolution mrm and sequential window acquisition of all theoretical fragment-ion acquisition modes for the quantitation of 48 wastewater-borne pollutants in lettuce

Screening of a large number of chemicals of emerging concern is highly desirable for the control of crops irrigated with reclaimed water since it is considered an alternative water source of great value. This study describes a high resolution mass spectrometry approach for developing methods for quantification in lettuce leaves of 48 different wastewater-borne pollutants (including analgesics and anti-inflammatories, anti-hypertensives, antifungal agents, lipid regulators, psychiatric drugs and stimulants, β-blockers, antibiotics, antimycotics, and sweeteners) frequently found in water resources. In this respect, a simple and fast QuEChERS-based method for the determination of contaminants in lettuce has been developed. During extraction, the use of formic acid was adopted to further improve the results of some problematic compounds (e.g., fenofibrate, furosemide, metronidazole, oxcarbazepine, sulfanilamide). High resolution multiple reaction monitoring (MRMHR) and SWATH acquisition were compared in term of accuracy, repeatability, sensitivity, linearity and matrix effect. Both methods provided similar recoveries between 80 and 120% in lettuce leaves, although sulfanilamide, ciprofloxacin, and sulfamethazine presenting values of 26.8, 27.8, and 28.4% in MRMHR and 25, 33.9, and 35% in SWATH, respectively. The effectiveness of a two-step cleanup on analyte recovery was also assessed and matrix effects were also taken into consideration during the method validation. The developed method allows the simultaneous quantitative analysis of 48 compounds (drug residues and metabolites) in lettuce leaves irrigated with treated wastewater for human consumption. Application of the present method to lettuce crops growth in controlled conditions showed the presence of 14 out 48 studied compounds with similar concentrations in both acquisition modes ranging from 3.3 and 1.3 ng g - 1 for climbazole (for MRMHR and SWATH, respectively) to 33.2 and 17.7 ng g - 1 for sulfamethazine. Drug residues such as carbamazepine (6.0 and 8.5 ng g - 1), and its metabolite carbamazepine epoxide (18.1 and 16.5 ng g - 1), frequently found in wastewater effluents, were also detected.

Development and Application of a Multi-Residue Method to Determine Pesticides in Agricultural Water Using QuEChERS Extraction and LC-MS/MS Analysis

Agricultural water is closely linked to surface and ground water as well as soil; hence, ensuring its safety is an important endeavor. We used the “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) method to analyze multi-residue pesticides in agricultural water by using a combined-sorbent-based clean-up procedure. Among the various sorbents examined, clean-up using ENVI-Carb combined with a primary secondary amine sorbent delivered the highest recovery of multi-residue pesticides (>93.9%). While the developed method showed satisfactory linearity (R2 > 0.9991), precision, and specificity, recovery was low for pyrazolate (29.1%) and thidiazuron (59.2%). The limits of detection and quantification for the 55 pesticides targeted in this study were in 0.02–3.0 μg L−1 and 0.1–9.9 μg L−1, respectively. The developed method was used to identify and quantify multi-residue pesticides during sample analysis. The results suggest that the QuEChERS method employing a combination of ENVI-Carb and another sorbent can be applied for the effective analysis of multi-residue pesticides in agricultural water.

Determination of Organochlorines in Soil of a Suburban Area of São Paulo Brazil

Technological advances have promoted improvements in several science fields, especially related to environmental and analytical areas with the improvement of detection and development of environmentally friendly extraction techniques. This study applied Quick, Easy, Cheap, Effective, Rugged and Safe method (QuEChERS) for soil extraction and assessed its performance through a validation study using samples from the soil of a contaminated area in Caieiras, SP, Brazil. Nine organochlorine pesticides, including the isomers alpha, beta, gamma and delta- hexachlorocyclohexane; cis- and trans-heptachlor epoxide; cis- and trans-chlordane and heptachlor were analyzed by gas chromatography coupled to electron capture detector. The method was validated according to ISO 5725-4 (2020), EURACHEM (2014) and DOQ-CGCRE-008 (2016). The limits of detection and quantification of the method for the nine organochlorines were α-HCH (1.2 and 12.6 µg kg^-1), β-HCH (1.7 and 12.0 µg kg^-1), γ-HCH (1.5 and 11.6 µg kg^-1), δ-HCH (0.8 and 11.6 µg kg^-1), heptachlor (1.0 and 10.8 µg kg^-1), cis-heptachlor epoxide (0.9 and 11.5 µg kg^-1), trans-heptachlor epoxide (0.9 and 11.5 µg kg^-1), cis-chlordane (0.4 and 7.9 µg kg^-1) and trans-chlordane (0.5 and 10.9 µg kg^-1), respectively, and all of them were within the maximum limits recommended by the EPA for the compounds α-HCH (86.0 and 360.0 µg kg^-1), β-HCH (300.0 and 1.3 × 10³ µg kg^-1), γ-HCH (570.0 and 2.5 × 10³ µg kg^-1), δ-HCH (not defined), heptachlor (130.0 and 630.0 µg kg^-1), cis-/trans-heptachlor epoxide (7.0 and 330.0 µg kg^-1), cis-/trans-chlordane (1.77 × 10³ and 7.7 × 10³ µg kg^-1) in residential and industrial soil, respectively. Recovery results were between 65% and 105% for almost all compounds, which is an optimum result for multi-residue analytical methods, considering the complexity of the matrix used in the study. Caieiras presented contamination levels of α-HCH in the range of 2.0 to 66.0 µg g^-1, which was higher than the limits established by EPA, corresponding to 0.077 µg g^-1 for residential soil and 0.27 µg g^-1 for industrial soil. According to the validation study, the analytical method proposed was reliable for organochlorine quantification, and the QuEChERS was considered efficient for organochlorine extraction from soil.

Development of a High Pressure Liquid Chromatography with Diode Array Detection Method for the Determination of Four Tetracycline Residues in Milk by Using QuEChERS Dispersive Extraction

QuEChERS (quick, easy, cheap, effective, rugged and safe) dispersive extraction was applied for the extraction of tetracyclines (oxytetracycline, tetracycline, chlorotetracycline and doxycycline) from milk. Target analytes were determined by an accurate and sensitive chromatographic analytical method, which was validated in terms of 2002/6572/EC decision. The analytes were separated on an Orbit 100C4 (5 μm, 250 × 4.0 mm) analytical column under a gradient mobile phase composed of a mixture of 0.01 M oxalic acid, 10−4 M Na2EDTA and acetonitrile. For the extraction of isolated compounds from sorbent, a methanol and 0.01 M oxalic acid mixture (1:1 v/v) was used, leading to relative recovery rates from 83.07% to 106.3% at concentration levels in the range 100–200 μg/kg. The within-laboratory reproducibility, expressed as a relative standard deviation, was <15.5%. Decision limits ranged between 100.3 μg/kg and 105.6 μg/kg and the detection capability varied between 100.6 μg/kg and 109.7 μg/kg. Ruggedness was evaluated by following the Youden approach, in terms of milk mass, sorbent mass, centrifugation time, vortex time, type and volume of organic solvents and evaporation temperature.

Validation, residue analysis, and risk assessment of fipronil and flonicamid in cotton (Gossypium sp.) samples and soil

Cotton crop is highly susceptible to attack by sucking pests. Being an important oilseed and feed crop, it is essential to monitor the pesticides and ensure health protection at consumer level. Therefore, a method was validated to estimate fipronil and flonicamid in various cotton samples and risk assessment was performed. Contamination of oil in the extracts from the various oil seeds and cake samples is a major problem as this oil contaminates the column and interferes with the detection of pesticides. The present manuscript for the first time describes successful analysis of the pesticides from various cotton samples including cotton oil, seed, and cake. Quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methods were validated for estimation of fipronil and flonicamid in cotton samples and in soil by LC-MS/MS. Recoveries were within the acceptable range of 70-120% with relative standard deviation ≤ 20% and HorRat values < 0.3-1.3. R² was > 0.99. Matrix effects of 150 and 13.5% were observed for fipronil and flonicamid, respectively, in cotton leaves. Limits of quantitation (LOQs) were in the range of 0.0004 to 0.004 mg kg^-1 for fipronil and flonicamid. Cotton samples collected from a field study at different locations were analyzed. Half-life ranged from 2.2 to 5.8 for fipronil and 4.6 to 7.0 days for flonicamid. A pre-harvest interval of 33 days is suggested. The risk assessment studies at maximum residue level values showed HQ < 1 at pre-harvest interval (PHI). The methods being short and easy can be extended to estimate more types of pesticides in different oilseeds. Following a PHI of 33 days, fipronil and flonicamid can be used on cotton at standard dose. As the levels of fipronil and flonicamid were below determination limit in all the soils, the environmental risk is negligible.

Long-Term Persistence of Pesticides and TPs in Archived Agricultural Soil Samples and Comparison with Pesticide Application

For polar and more degradable pesticides, not many data on long-term persistence in soil under field conditions and real application practices exist. To assess the persistence of pesticides in soil, a multiple-compound screening method (log K_ow 1.7-5.5) was developed based on pressurized liquid extraction, QuEChERS and LC-HRMS. The method was applied to study 80 polar pesticides and >90 transformation products (TPs) in archived topsoil samples from the Swiss Soil Monitoring Network (NABO) from 1995 to 2008 with known pesticide application patterns. The results reveal large variations between crop type and field sites. For the majority of the sites 10-15 pesticides were identified with a detection rate of 45% at concentrations between 1 and 330 μg/kg_dw in soil. Furthermore, TPs were detected in 47% of the cases where the "parent-compound" was applied. Overall, residues of about 80% of all applied pesticides could be detected with half of these found as TPs with a persistence of more than a decade.

Evaluation of alternative environmentally friendly matrix solid phase dispersion solid supports for the simultaneous extraction of 15 pesticides of different chemical classes from drinking water treatment sludge

This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses. Recoveries ranged from 70 to 120% with RSD below 20% for all analytes. Limits of quantification (LOQ) of the method ranged from 5 to 500 μg kg^-1 whereas the analytical curves showed correlation coefficients above 0.997. The method under investigation used low volume of solvent (5 mL), low sample mass (1.5 g) and low mass of chitin (0.5 g), an environmentally friendly support. It has advantages, such as speed, simplicity and low cost material, over other methods. When the method was applied, 4 out of 15 pesticides were detected in the DWTS samples in concentrations below the LOQ.

Influence of QuEChERS modifications on recovery and matrix effect during the multi-residue pesticide analysis in soil by GC/MS/MS and GC/ECD/NPD

A QuEChERS extraction followed by GC/MS/MS and GC-μECD/NPD for 216 pesticide and metabolites determination in soil simultaneously were developed and compared. Volume of water, volume and polarity of solvent, and cleanup sorbents (C18, GCB, PSA) were optimized. The QuEChERS with and without purification step were applied to estimate effectiveness of the method. The recovery and matrix effect (ME) were critical parameters within each tested procedure. The optimal method without cleanup was validated. Accuracy (expressed as recovery), precision (expressed as RSD), linearity, LOQ, and uncertainty were determined. The recoveries at the three spiking levels using matrix-matched standards ranged between 65 and 116% with RSD ≤17 and 60-112% with RSD ≤18% for MS/MS and μEC/NP, respectively. The LOQ ranged from 0.005-0.01 mg/kg for MS/MS to 0.05 mg/kg for μEC/NP. The ME for most of pesticides resulted in enhancement of the signal and depended on the analyte and detection system: MS/MS showed ME from -25 to 74%, while μEC/NP from -45 to 96%. A principal component analysis was performed to explain the relationships between physicochemical parameters and ME of 216 pesticides. The QuEChERS protocol without the cleanup step is a promising option to make the method less expensive and faster. This methodology was applied in routine analysis of 263 soil samples in which p,p' DDT was the most frequently detected (23.5% of samples) and pendimethalin with the highest concentration (1.63 mg/kg).

Freezing temperature controlled deep eutectic solvent dispersive liquid–liquid microextraction based on solidification of floating organic droplets for rapid determination of benzoylureas residual in water samples with assistance of metallic salt

A hydrophobic deep eutectic solvent worked as an extractant to extract benzoylureas with assistance of FeCl₃ contained dispersive-demulsified solvent.

Multiresidue determination of 29 pesticide residues in pepper through a modified QuEChERS method and gas chromatography-mass spectrometry

This study describes the development and use of a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with gas chromatography with mass spectrometry to determine 29 pesticide residues in green, red and dehydrated red peppers. Pesticides were extracted with acetonitrile (1% acetic acid), partitioned with sodium chloride and purified with primary secondary amino and octadecyl silane in acetone. The QuEChERS extraction conditions were optimized, and the matrix effects that might influence recoveries were evaluated and minimized using matrix-matched calibration curves. Under the optimized conditions, the calibration curves for 29 pesticides showed good linearity in the concentration range of 0.1-10 μg/mL with determination coefficient R(2)  > 0.998. The limits of quantification of the 29 pesticides were 0.006-0.06 mg/kg for green pepper, 0.005-0.039 mg/kg for red pepper and 0.014-0.25 mg/kg for dehydrated red pepper. These values are below the suggested regulatory maximum residue limits. The mean recoveries ranged between 70.1 and 110%, and the relative standard deviations were <13%. The developed method was successfully applied to commercial samples. Some samples were found to contain the 29 pesticides with levels below the legal limits. Copyright © 2016 John Wiley & Sons, Ltd.

Quantification of neonicotinoid insecticide residues in soils from cocoa plantations using a QuEChERS extraction procedure and LC-MS/MS

The use of neonicotinoids as an insecticide group in Ghana has been quite significant particularly in cocoa production. The high usage has been mainly as a result of a government policy of free insecticide spraying on cocoa farms, in an effort to curb declining yields caused by pests and diseases and to prevent the use of unapproved or banned insecticides on cocoa farms. However the scale of cocoa farming, the frequency and intensity of usage coupled with the mode of application may result in large physical volumes of insecticides in the environment. This makes the knowledge of the concentration and fate of neonicotinoids in the environment extremely important. The present study was aimed at assessing the levels of five major neonicotinoids in soils from cocoa farmlands in Ghana. Extraction and cleanup of analytes were performed by use of a method based on the original QuEChERS procedure after optimizing salts, sorbents and instrumental conditions. Analyte extraction with NaCl and MgSO4 in acidified acetonitrile followed by cleanup with primary secondary amine (PSA) presented the optimum conditions for extraction. Quantification was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). Validation of the procedure showed average recoveries ranging from 72.0 to 104.8% for all analytes at all fortification levels with relative standard deviation (RSD) ≤ 15.0. Limits of quantitation were <10 μg kg(-1) for all neonicotinoids studied. The results obtained from the analysis of 52 samples from cocoa farms revealed imidacloprid as the predominant neonicotinoid with concentrations ranging from 4.3 to 251.4 μg kg(-1) in >50% of samples analyzed.

Analysis of cyazofamid and its metabolite in the environmental and crop samples using LC-MS/MS

A rapid and robust LC-MS/MS method for the analysis of cyazofamid and its metabolite, 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM), in environmental samples (soil and water) and a variety of crops (apple, mandarin, Kimchi cabbage, green pepper, potato and soybean) was established in this study. Those compounds were analyzed by selected reaction monitoring with electrospray ionization (positive mode) on LC-MS/MS. Method limit of quantitations were 2 ng g(-1) (cyazofamid) and 5 ng g(-1) (CCIM) for soil/crop samples, while 0.02 ng mL(-1) (cyazofamid) and 0.05 ng mL(-1) (CCIM) were achieved for water samples. Matrix effect (%) was different depending on sample matrices. For recovery tests, soil/crop samples were treated with QuEChERS method and water samples were extracted with dichloromethane. The recoveries of target analytes in the environmental and crop samples were 80.2 %-105.1 % for cyazofamid and 75.1 %-99.1 % for CCIM (coefficients of variation; ≤16.4 %).

A method for determination of imazapic and imazethapyr residues in soil using an ultrasonic assisted extraction and LC-MS/MS

At least 52 % of the planted rice area in Rio Grande do Sul, a major rice producing state in Brazil, employs Clearfield(®) production system, corresponding to 580,000 ha of cultivated area. To grow rice with Clearfield(®) technology, producers combine imazethapyr and imazapic herbicides. However, these herbicides leave residual activity in soil; consequently, the repeated application of imazethapyr and imazapic on Brazilian Clearfield(®) rice fields has increased these herbicides persistence in treated soils. In this study, a method has been developed for removal and quantification of imazethapyr and imazapic residues in soil through ultrasonic assisted extraction using methanol-phosphoric acid aqueous solution (pH 2.0). The detected response was linear for both herbicides within the range of 0.25-5 ng mL(-1) with correlations coefficients >0.99. The quantification limit was limit of quantification 0.2 µg Kg(-1) for both pesticides. The good recovery rate from all pesticides, which ranges between 70 % and 120 %, demonstrates the method's validity.

Evaluation of the QuEChERS method for the extraction of pharmaceuticals and personal care products from drinking-water treatment sludge with determination by UPLC-ESI-MS/MS

A modified version of the QuEChERS method has been evaluated for the determination of 21 pharmaceuticals and 6 personal care products (PPCPs) in drinking-water sludge samples by employing ultra high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The performance of the method was evaluated through linearity, recovery, precision (intra-day), method detection and quantification limits (MDL and MQL) and matrix effect. The calibration curves prepared in acetonitrile and in the matrix extract showed a correlation coefficient ranging from 0.98 to 0.99. MQLs values were on the ng g(-1) order of magnitude for most compounds. Recoveries between 50% and 93% were reached with RSDs lower than 10% for most compounds. Matrix effect was almost absent with values lower than 16% for 93% of the compounds. By coupling a quick and simple extraction called QuEChERS with the UPLC-MS/MS analysis, a method that is both selective and sensitive was obtained. This methodology was successfully applied to real samples and caffeine and benzophenone-3 were detected in ng g(-1) levels.

A quick, easy, cheap, effective, rugged and safe extraction method followed by liquid chromatography-(Orbitrap) high resolution mass spectrometry to determine benzotriazole, benzothiazole and benzenesulfonamide derivates in sewage sludge

A Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction method followed by liquid chromatography-(Orbitrap) high resolution mass spectrometry was developed for the simultaneous determination of five benzotriazole, four benzothiazole and five benzenesulfonamide derivates in sewage sludge. While the method was being developed, several buffers and dispersive solid-phase extraction clean-up (dSPE) sorbents were tested. Citrate buffer and Z-sep+ (zirconium-based sorbent) were the most effective extraction buffer and dSPE clean-up material. The absolute recoveries were higher than 80% for all compounds (100ng/g (d.w.)) and the matrix effect was less than -20% for most compounds. The limits of detection were between 0.5 and 10ng/g (d.w.) and the limits of quantification (LOQ) were between 1 and 25ng/g (d.w.). Repeatability and reproducibility were lower than 15% (%RSD, n=5). Several sludge samples from five sewage treatment plants in Catalonia were analysed and the most abundant compounds were 2-hydroxybenzothiazole ( Collapse

Key Words

• Benzenesulfonamides
• Benzothiazoles
• Benzotriazoles
• Liquid chromatography-high resolution mass spectrometry
• QuEChERS
• Sewage sludge

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MESH Headings

• Benzothiazoles/analysis
• Chromatography, High Pressure Liquid
• Limit of Detection
• Mass Spectrometry
• Reproducibility of Results
• Sewage/chemistry
• Solid Phase Extraction
• Sulfonamides/analysis
• Triazoles/analysis
• Water Pollutants, Chemical/analysis
• Benzenesulfonamides

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Affiliation(s)

Pol Herrero Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Sescelades Campus, Marcel·lí Domingo s/n, 43007 Tarragona, Spain
Francesc Borrull Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Sescelades Campus, Marcel·lí Domingo s/n, 43007 Tarragona, Spain
Eva Pocurull Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Sescelades Campus, Marcel·lí Domingo s/n, 43007 Tarragona, Spain.
Rosa M Marcé Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Sescelades Campus, Marcel·lí Domingo s/n, 43007 Tarragona, Spain

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